Forging machine

ABSTRACT

A forging machine is disclosed having two pairs of opposed rams uniformly and angularly spaced around a workpiece feeding axis. Each ram has two working hydraulic actuator pistons for moving the ram in a working stroke, and a single retracting hydraulic actuator piston for retracting the ram. Two pump units are provided, one opposite the other, on opposite side of the machine. Each pump unit services two rams, one from each of the two pairs of rams, in order that the rams may be simultaneously driven in working and retracting strokes to forge a workpiece being fed along the workpiece feeding axis.

United States Patent Kralowetz et al.

[451 Aug. .8, 1972 [54] FORGING MACHINE [72] Inventors: Bruno Kralowetz,St. Ulrich near Steyr; Othmar Heimel, Behamberg, both of Austria [22]Filed: Dec. 16, 1970 [21] Appl. No.: 98,750

[30] Foreign Application Priority Data 2,002,289 5/1935 Hancock ..72/4502,203,956 6/1940 Gettig .72/402 2,182,663 12/1939 Ely ..72/402 3,372,5703/1968 Mansell ..72/453 3,375,931 12/1967 Kralowetz ..72/453 3,45 1,2496/ 1969 Sharon ..72/453 Primary Examiner-Charles W. Lanham AssistantExaminer-Gene P. Crosby Attorney-Kurt Kelman [57] ABSTRACT A forgingmachine is disclosed having two pairs of opposed rams uniformly andangularly spaced around a workpiece feeding axis. Each ram has twoworking hydraulic actuator pistons for moving the ram in -a workingstroke, and a single retracting hydraulic actuator piston for retractingthe ram. Two pump units are provided, one opposite the other, onopposite side of the machine. Each pump unit services two rams, one fromeach of the two pairs of rams, in order that the rams may besimultaneously driven in working and retracting strokes to forge aworkpiece being fed along the workpiece feeding axis.

4 Claim, 2 Drawing Figures PATENTEDAus- 8 I972 RR HEIMEL.

HGENT FORGING MACHINE This invention relates to a forging machine whichcomprises four forging rams which are angularly spaced 90 apart, or twomutually opposite forging rams, which rams extend and are displaceableradially with respect to the axis of the workpiece and at their endcarry shaping tools and are movable by means of hydraulic actuators.

Such forging machines are mainly intended for shaping workpieces havinglarge dimensions in cross-section and consisting of such materials thatit is difl'rcult to roll them directly from the ingot. The shaping ofsuch workpieces gives rise to high torques so that the members of thedrive means of the known and welltried forging machines which aremechanically driven must be so large and strong that the manufacture ofthe machine would not be economical.

A forging machine isknown in which the shaping tools are hydraulicallydriven. These tools are directly secured to the four forging rams formedby the pistons or piston rods of the hydraulic actuators and the workingstroke is derived from four pump pistons, which are rigidly connectedand disposed one beside the other and mounted on another reciprocatingpiston or the like and which are movable in cylinders communicating withthose cylinder chambers of the actuators which are remote from theworkpiece. Retracting ac- .under pressure from respective accumulators.That known machine has various disadvantages. Because the pump pistonsassociated with all four actuators are disposed adjacent to each other,some of the conduits which connect the pump cylinders and the cylindersof the actuators must be relatively long. Because the hydraulic fluid iscompressible to some extent and the long conduits can elastically defonnunder the high pressures applied, oscillations or the like may arise inthe hydraulic systems and may prevent an exact or dimensionally accurateforging operation. Besides, that known machine cannot be designed tohave a closely arranged, compact structure. The hydraulic accumulatorsprovided for the retracting actuators add to the structural expenditure.Besides, each of the forging rams which form also the pistons or pistonrods of the hydraulic actuators is provided with only one sliding guide,which is disposed between he pistons and the workpiece. Because thelines of action of the forces which occur are not always exactly alignedwith the axis of the piston or ram, a canting and at least an increasedwear in the cylinders of the hydraulic actuators may result.

It is an object of the invention to eliminate these disadvantages and toprovide a forging machine of the kind defined first hereinbefore, whichmachine is comparatively simple and compact in structure and in whichoscillations or the like in the hydraulic systems are avoided as far aspossible and no difficulties are involved in the guidance of the rams.

This object is accomplished according to the invention in that eachforging ram is provided with two spaced apart sliding guides and atleast two hydraulic actuators for the working movement, which actuatorsare uniformly spaced around the axis of the ram, and an axial retractinghydraulic actuator, and the hydraulic actuators of each pair of directlyadjacent forging rams have associated with them a pump unit, which issecured to the machine housing and comprises two large piston pumpshaving a relatively large effective piston area,- two small piston pumpsand two eccentric shafts rotating in synchronism, each of said eccentricshafts being connected by an elliptic chuck or the like to a largepiston pump and a small piston pump which is coaxial with and disposedopposite to said large piston pump, said large piston pumps supplyingpressure fluid to said actuators for the working movement and said smallpiston pumps supplying pressure fluid to the retracting actuators.Because each forging ram is provided with two sliding guides which arespaced a suitable distance apart, all forces can be taken upsatisfactorily and canting or the like can beavoided. Since the workingmovement is imparted to the rams by actuators which are uniformly spacedaround the axis of the ram, no torque is developed by the forcestransmitted from the actuators to the rams. As a pump unit is associatedwith each pair of directly adjacent forging rams and the actuators forthese rams, said pump unit may be secured to the machine housing veryclose to the actuators so that the conduits which connect the pumpcylinders to the cylinder chambers of the actuators are as short aspossible, the liquid cushions are relatively small, and oscillations orthe like in the hydraulic systems are substantially avoided. Besides,the forging machine has a simple, compact and clearly arrangedstructure. The working stroke is derived from the two large piston pumpswhich are connected to the actuators for the working movement of therams whereas the small piston pumps serve to retract the pistons so thataccumulators are not needed for this purpose. The retracting actuatormay be coaxial with the associated ram because the retracting strokerequires only much smaller forces and the forging reaction forces neednot be allowed in this stroke. As a larger piston pump and a smaller oneare coaxially arranged opposite to each other and driven by the sameeccentric, the pistons of these pumps will move in phase opposition sothat the pressure stroke of one pump piston and the suction stroke ofthe other pump piston will be necessarily performed at the same time,the supply of pressure fluid to the actuators will be properly timed ina simple manner, and it is sufficient to supply pressure fluid to onlyone end of each piston of all actuators. The arrangement may be suchthat the larger of the two piston pumps driven by a common eccentric isassociated with the actuator for the working movement of one forging ramand the smaller of these two pumps is associated with the retractingactuator of the adjacent forging ram so that the connecting conduits arefurther reduced in length. It will be understood that in machinescomprising four forging rams the two pump units will be synchronized orhave a common drive means.

A desirable and space-saving design of the pump unit will be obtained ifthe piston pumps thereof are arranged so that a larger piston pump and asmaller one are disposed one beside the other with parallel axes and theeccentrics of the two parallel eccentric shafts are relatively displacedin phase so that the supply of pressure fluid to the actuators isproperly timed.

An embodiment of the invention is shown by way of example in simplifiedor diagrammatic views in the accompanying drawing, in which FIG. 1 is apartly sectional view showing an overallmachine and FIG. 2 is anenlarged sectional view showing the pump unit and taken on line lIIl inFIG. 1.

A forging housing 1 comprises four forging rams 3, 3a, 4, 4a, whichcarry shaping tools 5 at their ends. The rams extend radially withrespect to a workpiece axis 2 and are angularly spaced 90 apart andinclined by an angle of 45 from the horizontal. Each of the forging rams3, 3a, 4, 4a carries at its end face a shaping tool 5 and is providedwith two sliding guides 6, 7 which are considerably spaced apart. Theforging rams are held against rotation, of course. Each forging ram isconnected to two hydraulic actuators 8, which are symmetrically disposedwith respect to the axis of the ram. It will be understood thathydraulic actuators may be provided in a larger number and uniformlyspaced around the axis of the ram. These actuators 8 impart to theforging rams 3, 3a, 4, 4a the working movement, i.e., the stroke of theram toward the workpiece. The rams are retracted from the workpiece byretracting actuators 9. Pressure is supplied only to one end of each ofthe actuators 8 and 9.

The actuators 8, 9 for each pair of directly adjacent forging rams 3, 3aor 4, 4a are associated with a pump unit 10, 11, which is secured to theside of the machine housing 1. Each of these units 10, 11 comprises twolarge piston pumps 12, 120, which have a relatively large piston area,two small piston pumps 13, 13a, and two parallel eccentric shafts 14,15, whose eccentrics l6, 17 are displaced 180 in phase but may be drivenin synchronism by a common spur gear train 18. The eccentrics 16, 17 aresurrounded by links 18 of elliptic chucks having spiders 19, in whichthe links are slidable and which are directly connected to the pumppistons.

so that each revolution of the eccentric shafts results in anup-and-down motion of the pistons of the pumps 12,

13a and 12a, 13, respectively. The cylinder chamber of the piston pump12 is connected by two conduits 20 to the actuators 8 for the ram 3. Thecylinder chamber of the piston pump 13a is connected by a conduit 21 tothe retracting actuator 9 for the ram 30. A conduit 22 extends from theretracting actuator 9 for the ram 3 to the piston pump 13. The pistonpump 12a supplies pressure fluid to the hydraulic actuators 8 forimparting a working movement to the ram 3a. Hence, the working movementof the rams 3, 3a is derived from the large piston pumps 12, 13a and theretracting movements of these rams are derived from the small pistonpumps 13, 13a. The arrangement is such that the conduits from the pistonpumps to the hydraulic actuators are as short as possible and the supplyof pressure fluid to these actuators is properly timed. Similarly, thepump unit 11 supplies pressure fluid to the hydraulic actuators for therams 4, 4a. The two units 10, 11 are operated in synchronism or have acommon drive shaft 23.

Because the rams 3, 3a, 4, 4a have guided in accordance with theinvention in the sliding guides 6, 7, any transverse or tilting ortwisting forces which may be due to an eccentric action of force on theshaping tools 5 are withhold from the sensitive actuators 8. Only whenthe forging rams perform a transverse movement owing to the inevitableplay in the guide are the corresponding pistons slightly canted; thiscanting can be taken into account by a carnbered shape of the pistonsand the provision of a floating seal preventing a leakage of oil at thepiston rod. With this arrangement, the machine will operate reliablyeven when the sliding guides 6, 7 have suffered substantial wear. Allhydraulic means are desirably disposed outside the range in which theywould be subjected to the action of heat from the incandescentworkpiece. Finally, the sliding guides for the rams may be lubricatedwith heavybodied oil independently of the hydraulic system. The forgingmachine need not essentially comprise four forging rams because only twoforging rams, which are disposed diametrically opposite to each other,may be suflicient in some cases.

What is claimed is:

1. A forging machine, which comprises a machine housing defining afeeding path for a workpiece, which feeding path has an axis,

one to two pairs of forging rams, which are uniformly angularly spacedaround said axis and extend and are displaceable radially with respectto said axis to perform a working stroke toward said axis and aretracting stroke away from said axis, each of said rams having an innerend which faces said axis and carries a shaping tool, the rams of eachpair being directly angularly adjacent to each other,

a plurality of pairs of sliding guides, the sliding guides of each ofsaid pairs thereof being arranged to guide one of said rams in thelongitudinal direction thereof and being spaced apart in saidlongitudinal direction,

a plurality of sets of working hydraulic actuators, each of which setsis associated with one of said rams and comprises a plurality ofactuators uniformly angularly spaced around the associated ram andoperable to impart said working stroke thereto,

a plurality of. retracting hydraulic actuators, each of which isassociated with one of 4 said rams and operable to impart saidretracting stroke to said ram, and

pump means comprising for each of said pairs of rams a pump unit, whichis secured to said machine housing laterally of said axis and comprisestwo large piston pumps, two small piston pumps having a smaller pistonarea than said large piston pumps, each of said large piston pumps beingcoaxial with and disposed opposite to one of said small piston pumps,and two eccentric shafts, each of which is operatively connected to oneof said large piston pumps and to the small piston pump which is coaxialwith and disposed opposite to said one large piston pump,

said machine further comprising 7,

drive means operable to rotate said two eccentric shafts of each of saidpump units in synchronism, and

conduit means for supplying pressure fluid from each of said largepiston pumps to said working actuators associated with one of said ramsof the associated pair, and from each of said small pumps to saidretracting actuator associated with one of said rams of the associatedpair.

that one of said large piston pumps and one of said small piston pumpsare disposed one beside the other with parallel axes,

said two eccentric shafts are parallel,

each of said eccentric shafts carries an eccentric, and

said eccentrics on the two eccentric shafts of each pump units arerelatively disposed in phase.

1. A forging machine, which comprises a machine housing defining afeeding path for a workpiece, which feeding path has an axis, one to twopairs of forging rams, which are uniformly angularly spaced around saidaxis and extend and are displaceable radially with respect to said axisto perform a working stroke toward said axis and a retracting strokeaway from said axis, each of said rams having an inner end which facessaid axis and carries a shaping tool, the rams of each pair beingdirectly angularly adjacent to each other, a plurality of pairs ofsliding guides, the sliding guides of each of said pairs thereof beingarranged to guide one of said rams in the longitudinal direction thereofand being spaced apart in said longitudinal direction, a plurality ofsets of working hydraulic actuators, each of which sets is associatedwith one of said rams and comprises a plurality of actuators uniformlyangularly spaced around the associated ram and operable to impart saidworking stroke thereto, a plurality of retracting hydraulic actuators,each of which is associated with one of said rams and operable to impartsaid retracting stroke to said ram, and pump means comprising for eachof said pairs of rams a pump unit, which is secured to said machinehousing laterally of said axis and comprises two large piston pumps, twosmall piston pumps having a smaller piston area than said large pistonpumps, each of said large piston pumps being coaxial with and disposedopposite to one of said small piston pumps, and two eccentric shafts,each of which is operatively connected to one of said large piston pumpsand to the small piston pump which is coaxial with and disposed oppositeto said one large piston pump, said machine further comprising drivemeans operable to rotate said two eccentric shafts of each of said pumpunits in synchronism, and conduit means for supplying pressure fluidfrom each of said large piston pumps to said working actuatorsassociated with one of said rams of the associated pair, and from eachof said small pumps to said retracting actuator associated with one ofsaid rams of the associated pair.
 2. A forging machine as set forth inclaim 1, which comprises two of said pairs of rams and in which saidrams are angularly spaced 90* apart.
 3. A forging machine as set forthin claim 1, in which each of said eccentric shafts is operativelyconnected by an elliptic chuck to the piston pumps associated therewith.4. A forging machine as set forth in claim 1, in which the piston pumpsin each pump unit are arranged so that one of said large piston pumpsand one of said small piston pumps are disposed one beside the otherwith parallel axes, said two eccentric shafts are parallel, each of saideccentric shafts carries an eccentric, and said eccentrics on the twoeccentric shafts of each pump units are relatively disposed 180* inphase.